//
// detail/executor_op.hpp
// ~~~~~~~~~~~~~~~~~~~~~~
//
// Copyright (c) 2003-2022 Christopher M. Kohlhoff (chris at kohlhoff dot com)
//
// Distributed under the Boost Software License, Version 1.0. (See accompanying
// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
//

#ifndef ASIO_DETAIL_EXECUTOR_OP_HPP
#define ASIO_DETAIL_EXECUTOR_OP_HPP

#if defined(_MSC_VER) && (_MSC_VER >= 1200)
# pragma once
#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)

#include "asio/detail/config.hpp"
#include "asio/detail/fenced_block.hpp"
#include "asio/detail/handler_alloc_helpers.hpp"
#include "asio/detail/handler_invoke_helpers.hpp"
#include "asio/detail/scheduler_operation.hpp"

#include "asio/detail/push_options.hpp"

namespace asio {
    namespace detail {

        template<typename Handler, typename Alloc,
                typename Operation = scheduler_operation>
        class executor_op : public Operation {
        public:
            ASIO_DEFINE_HANDLER_ALLOCATOR_PTR(executor_op);

            template<typename H>
            executor_op (ASIO_MOVE_ARG(H)

            h,
            const Alloc &allocator
            )
            :

            Operation (&executor_op::do_complete),
            handler_(ASIO_MOVE_CAST(H)(h)),
            allocator_(allocator) {
            }

            static void do_complete(void *owner, Operation *base,
                                    const asio::error_code & /*ec*/,
                                    std::size_t /*bytes_transferred*/) {
                // Take ownership of the handler object.
                executor_op * o(static_cast<executor_op *>(base));
                Alloc allocator(o->allocator_);
                ptr p = {detail::addressof(allocator), o, o};

                ASIO_HANDLER_COMPLETION((*o));

                // Make a copy of the handler so that the memory can be deallocated before
                // the upcall is made. Even if we're not about to make an upcall, a
                // sub-object of the handler may be the true owner of the memory associated
                // with the handler. Consequently, a local copy of the handler is required
                // to ensure that any owning sub-object remains valid until after we have
                // deallocated the memory here.
                Handler handler(ASIO_MOVE_CAST(Handler)(o->handler_));
                p.reset();

                // Make the upcall if required.
                if (owner) {
                    fenced_block b(fenced_block::half);
                    ASIO_HANDLER_INVOCATION_BEGIN(());
                    asio_handler_invoke_helpers::invoke(handler, handler);
                    ASIO_HANDLER_INVOCATION_END;
                }
            }

        private:
            Handler handler_;
            Alloc allocator_;
        };

    } // namespace detail
} // namespace asio

#include "asio/detail/pop_options.hpp"

#endif // ASIO_DETAIL_EXECUTOR_OP_HPP
